Barracuda Networks released a new update on Monday to further mitigate a security issue that could have allowed attackers to gain unauthorized access to some of its network security appliances through backdoor accounts originally intended for remote support. The company apologized to customers for its design decisions that led to this situation and promised to look into additional ways to strengthen the remote support functionality.

Two weeks ago, security researchers from Austria-based security firm SEC Consult, revealed that Barracuda Networks appliances contain several undocumented -- backdoor -- accounts. Furthermore, the default firewall configuration of those devices made it possible for attackers to access the undocumented accounts from a predefined set of public IP (Internet Protocol) addresses, some of which did not belong to Barracuda Networks.

The company responded at the time by releasing a "Security Definition" update that it claimed "drastically minimized attack vectors" by disabling remote access to non-essential accounts. However, on Monday the company released a new update -- Security Definition 2.0.7 -- to further mitigate the issue by removing the unauthorized IP address ranges from the default firewall rules.

"The security and remote access functionality recently reported by a security researcher were implemented years ago, and were not diligently updated as our network evolved," Barracuda Networks co-founder and Chief Technology Officer Zach Levow, said Monday in a blog post.

"Over the years, we've made support our main focus, doing as much as possible to provide the best support to our customers," Levow said. "However, I realize that in doing so, we missed the balance required in today's security and network environment. We overlooked the importance of not putting support controls front and center in the user interface, and the issues related to making support access opt-out rather than opt-in if certain appliances are not behind a firewall. I regret now some of the choices we made and apologize to our customers and partners who feel misled or deceived by the way it was implemented. I assure you we are working day and night to make further changes that integrate the feedback and expectations you have shared with us."

While the new security updates considerably restrict the ability of attackers to gain unauthorized access to Barracuda devices through the remote support feature, they do not remove the feature completely. Barracuda support technicians can still remotely access appliances if they are directly connected to the Internet, an ability that some customers might not be comfortable with.

"While we speak openly about our ability to remotely support customer boxes, the implications of this type of deployment are not explicitly documented," Levow said. "We encourage customers to deploy their appliances behind a firewall that is configured to pass only traffic intended for the appliance."

Barracuda is currently analyzing ways to change the feature so that establishing a remote support tunnel would require customer interaction even if the appliance is connected directly to the Internet, Levow said.